In my layman opinion the correct solution would be a directed-energy weapon. The most obvious one that comes to mind would be a laser (or an array of lasers, for your dozen-fast flying drone scenario). Imagine the large collection of lights that point multi-directionally behind rockstars at concerts; except, in the future, these are all defensive lasers to defend against a worst-case scenario. Ha, would probably be very impractical except for defending heads of state and the like.
There're relatively easy countermeasures against that too: reflective paint and a rolling airframe. To be effective the laser needs to heat the airframe fast enough to cause structural damage before the energy is dissipated away. This is relatively easy when you're targeting a black plastic drone that remains stationary in the sky. It becomes orders of magnitude less effective when the drone is white or metallic and the point of contact moves all over the drone, particular because flying objects have natural air cooling to dissipate energy away.
Lasers have been demonstrated strong enough that those countermeasures are insufficient.
Bigger problem is, if you’re a politician and this scenario plays out during a rally, you just blinded your own supporters by shining a metal-melting laser at a shiny bauble while it was just above their heads.
I haven't seen any demonstration of a laser destroying a rolling airframe with reflective coatings. The only practical demonstration I could find anywhere was a laser on a boat burning one single drone that was gray in color, from only about 800m away. And it took about ten seconds to do so.
Most of my search results today are CGI propaganda pieces, the closest I can find is this from 2013, which is just a normal non-shiny and probably non-spinning missile, but from 1.5km and being destroyed 4s after launch: https://youtu.be/kgUnDeED9MM
